<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
</head>
<body>
    
</body>
<script>

    // var num1 = 30000;
    // var num2 = prompt('请输入你的绩效工资');
    // var num3 = Number(num2);
    // var num4 = num1 + num3;
    // alert('你的总工资为' + num4);

    var num1 = prompt('第一个数字为');
    var num2 = Number(num1);
    var num3 = prompt('第二个数字为');
    var num4 = Number(num3);
    alert(num2 + num4);
</script>
</html>